Device for restricting axial movements of shafts.



F. 64 B.l;1UN(iSTROM.

DEVICE FOR RESFRICWNG AXIM. MOVEMENTS 0F SHAFTS.

APPLICATION FILED FEB. 25, 1917.

V Patented May 1, 1917.

Inventors:

Fredrik Ljungstrc'im, Birger Ljun strom.

Their Attorne Y Fnnnmx mpnesrnoivi AND 31mm munesrn'oivi, or FINSPONG,swnnnn, Assienons TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEWYORK.

nnvlonron nnstrnic'rine AXIAL MOVEMENTS or SHAFTS.

Specification of Letters Patent.

Patented May i, 1917.

Application filed February 26, 1917. Serial No. 151,117.

- To all'whom it may concern:

' Be it known that we, FREDRIK LJUNG- sTRtSM and BIRGER LJUNos'rRoM,subjects of the King of Sweden, residing at Finspong, in the Kingdom ofSweden, have invented certain new and useful Improvements in Devices forRestricting Axial Movements .of Shafts, of which the following is aspecification.

In connection with certain types of apparatus, notably elastic fluidturbines, devices are provided to. restrict axial movements of theshaftor shafts. As commonly constructed these devices comprise astationary l5 cylinder containing a piston which is attached toandirotated by the shaft whose axial movements it is desired to restrictor dampen. A fluid, such as oil, is admitted to the cylinder on oppositesides of the roftating piston, which fluid is forced through suitablyrestricted valved passages from one end .of the cylinder to the other asthe shaft and piston move axially.

This construction is open tocertain disadvantages. The rapid rotation ofthe piston causes the ,oil to heat and. generate gases which-interferewith the proper functioning ofgtheparts. As the viscosity of the oil isgreater cold than hot this gives rise to a greater damping effect in theone case than in the other. Further. the slight wear of the slidingparts due to use gives rise to leakages which change the effect of thedampin action, and it is diliicult or impossible to adjust the parts tocompensate therefor.

The object of the present invention is to provide a damping device whichis free from the objections above noted and which is of simple andrugged construction.

In the following description reference will be made to the dampingofaxial movements of turbine rotor shafts but it is to be understoodthat the invention" is not neces- Sarilyliini'ted thereto since. it. iscapable of wider application.

For a consideration of what we believe to be. noveland our inventionfattention is directed to; the accompanying description and I 5 claimsappended thereto.

In the accompanying illustrative of the invention Figure l s alongitudinalisection of one' form' of the 111- vention, and Fig. 2 is asim lar section showinga means for automatically compensating for wear.

drawing which is a indicates a head or member whose axial movements areto be restricted or damped. In-the present instance it is intended to beattache'd to or form a part of the rotating blade structure of anelastic fluid turbine. To the head or member is attached a smallflexible shaft Z), the right hand end of which is firmly attached to adisk 0, forming a part of a slip=joint. On oppositesides of the disk arerows of hardened steel balls (Z and 5 6 located in ball races f and g,forming the stationary part of the slip-joint. The outer surfaces of theball races are made spherical and are seated on inwardly facing seats orparts h and 2' which are carried by the axi- 7o ally moving hollowpiston is. The seat It I is or may be formed integral with the pistonwhile the seat 6 is made in the form of a ring nut and is screw threadedinto the piston. The purpose of this latter arrangement is to permit therotating disk cand associated bearing balls to be mounted in place.Thepurpose of the rows of balls is to permit the disk 0 to be rotatedrelatively to the piston and at the same time to transso mit theretoaxial movement of the turbine or other shaft. The spherical surfaces onthe parts 7 and 9 permit the disk 0 to adjust itself on the seatsthereby compensating for any lack of alinement between the driving asmember a and the piston and its inclosing I cylinder. In other words thearrangement .of thespherical surfaced parts f and g and the seats h and2' forms a universal joint The piston is located within the cylinder lto which when in use is restrained by any suitable means from moving inany dire 'ion. The cylinder is counterbored for a portion of its lengthand located therein is a means for creating a certain amount of frictionbe- M5 tween the piston and the cylinder. As shown said means comprisesa plurality of packing rings in of any suitable character.

.Experience has demonstrated that leather is suitable for thepurpose. Inorder to give the rings the necessary initial compression and also toadjust them to compensate for wear a'followe'r n is provided that fitsthe wall of the counter bore and engages the rings. This follower isforced into position by the nut 0 which has suitable aXially'extendingholes t to receive a spanner wrench. The right hand end of the cylinderisclosed by a screw threaded cover or nut s.

The eripheral surface of the piston and 11d the surrounding parts aresupplied with lubricant from a groove in the cylinder which communicateswith the supply pass sage 1). Any excess of lubricant escapes into endof the cy l of the invention wherein a stiff coiled c.om pression springr is interposed between the. nut o and the'followenm'the constructionotherwise. being the same. The purpose of this spring is to maintain" amthe leather rings.

be chosen with this in view'.'. I!

The operation of the device'is as follows: vWhen the turbine or othershaft is rotated the. member a, shaft band disk 0 also'rotate, thelatter between the rowsofballs dijzind, e;

In case the axis of the turbine or other drivin shaft does not exactlycoincidewith the ax1s of the piston and its cylinder 'or the shaft does'not'run true for any -reason the outer spherical surfaces of the ballraces will swing or move 'a sufficient amount on their seats tocompensate therefor. On the other hand any force exerted onthe turbineor other shaft tending to move it axially in either direction will beresisted until suchforce is sufficient to overcome'the friction exertedby the packing rings on the piston.

In -the'latter case the shafflwill of course,

move but will do so in a sluggish manner and thus prevent axialvibrations which might otherwise take place.

When the damping effect decreases below the desired value it is asimplematter to remove the outer cap and screw in the nut 0 thus forcing thefollower to compress the packing until the desired friction is reesatablished. In case a spring of proper form is employed; as in Fig. 2,,thiszadjustment will take place, automatically.

The nut ishould be so adjusted as to eliminate any axial play-of theballs in their races. If, however, an. lo'oseness or, play' does existcentrifugal. orce. acting on the balls as they rotate with the disk willcause the balls to more outwardly and take up said play.

In accordance with the provisions of the patent statutes, wehavedescribed the prinwith the apparatus which we now consider to representthe best embodiment thereof; but we desire to have it understood thatthe apparatus shown is only illustrative, and that the invention can becarried out by other means. a a o What we claim as new and desire to secure by Letters Patent is:

1. A device for suppressing axial oscillat- 05 ing movements of arotating shaft, compris- Ifor adjusting the pressure of the friction ingmovement of the shaft, a cylinder inciple of operation of our invention,together ing a'movable member connected with the shaft, a stationarymember, a friction device .'interposed between .the Tmogable and'resnectt'o said movable member. y '2. Afdevice for suppressing axialoscil- ..lating ln(' v'ement s of a. rotating shaft, comprisingafmovable membericoiinected with .the shaft, asta'tionary member, afriction stantia-lly uniform pressure ontli'e friction means and inthismanner com en'sate,;fer :i'ny earer;

i e Wif o Sp ng n the tension to which, it is subjected should;

deyice interposed between' thermovable and pose a displacement of theshaft, means a1"- lowingthe shaft to rotate freely, and means vv devicev f devicefor suppressing axial oscillatfing" movements of a rotatingshaft, comprising a bearing connected to and moved 85.

by the shaft, a "stationary member and a' -fricti'ondevice interposedbetween the hearing and the stationary member and adapted to oppose adisplacement ofthe shaft and the bearing. i v

- 4. A device for. suppressing axial oscildating movements-of a rotatingshaft, comprising a hollow piston, means connecting theshaft and pistonso as to allow a swingclosing the piston, and a friction-deviceinterposed between the piston and the cylinder and adapted to oppose adisplacement of the shaft.

5. A device for suppressing axial oscillating movements ofa rotatingshaft, comprising an ax'al bearing for the shaft'ada ted to allow aswinging movement thereof a hollow. piston forming the stationary part.of said bearing, a cylinder inclosing the pisw ton, and africtiondevice interposed between the piston and the cylinder and adapted tooppose axial displacement of the shaft.

6. A device for suppressing axial Inove-- ments of a rotating shaft,comprising a means rotated by the shaft whose axial movements are to be-damped,"a pair of relatively movable members, a slip-joint whichpermits the transfer of one kind of movements from said means to one ofthe members and prevents others, and a friction means between themembers to restrict relative movements thereof.

7. A device for suppressing axial move- 1 20 shaftwith the piston andpermits ofa limited universal movement of one with respect to "the otherat the same time permitting the v shaftto'rotate', a cylinder for thepiston, a

friction device comprising a packing which is located between the pistonand vlinder and is supported by one of them, afollower for subjectingthe packing to pressure to ments of a rotating shaft. comprising apistonand cylinder, a member adapted to be connected to the rotatingshafthand the pis ton, a bearing that connects the member with thepiston and permits the member to rotate independently of the piston andalso to move it axially, a friction device between the piston andcylinder to restrict relative movements thereof and an elastic meanswhich subjects the friction device to a subi stantially constantpressure.

9. A device for suppressing axial move- 'ments of a rotating shaft,comprising a hollow piston and cylinder, a disk adapted to be rotated bythe shaft, bearings on. opposite sides of the disk having sphericalsurfaced members, seats for the members cark-ried by the piston, and anadjustable pack 311g device located between the adjacent sur- 'faces. ofthe piston and cylinder to restrict axialfmovements of one with respectto the other.

In testimony whereof we aiiix our signatures in presence of twowitnesses.

FREDRIK LJUNGSTROM. BIRGER LJUNGSTRUM.

Witnesses ELI" VAHMAN, G. inarunv

